At present, no methods are suitable for concentrating viruses from foods such as hamburger. We have surveyed the literature and examined the most promising published methods; none were satisfactory. As a next step, we will investigate the use of immuno-absorbants for virus isolation, so viruses that are present in low numbers in foods can be concentrated before inoculation into tissue cultures. The immuno-absorption method should also impart specificity to the isolation procedure as well as increase recoveries and decrease the time needed for virus concentration. Previously-modified immuno-EM procedures will be used for virus identification. We will also initiate studies to determine the relationships between numbers of enteroviruses in selected foods and numbers of fecal Escherichia coli and enterococci, which are bacterial indicators of food pollution.